1. Field of the Invention
This invention relates in general to visual displays and in particular to a visual display translated from musical sound.
2. Prior Art
The patent to Rand, U.S. Pat. No. 4,790,629, issued on Dec. 13, 1988, for Visual Display System With Triangular Cells, discloses a display consisting of a regular pattern of adjacent isosceles triangles which may be formed into numerous geometric shapes. Each cell contains four filament type light sources, color filters, and a flat translucent light diffusing surface. The triangular outline shape is formed by opague interior light baffles. The apparatus employs a digital information processor and storage tables to facilitate the storage of color and intensity values for each cell. A keyboard is provided whereby during operation a key closure will cause automatic execution of a preselected lighting effect to be produced.
The patent to Swinton, U.S. Pat. No. 4,713,658, issued on Dec. 15, 1987, for Apparatus For Providing A Visual Interpetation Of An Audio Signal, discloses means to electronically analyze a musical signal into components based on the frequency or amplitude characteristics of the signal. These component signals are used to operate electric motors and lamps. A motor rotates a primary shaft to which is attached multiple secondary motors and shafts which in turn rotate multiple decoratively shaped fin assemblies. The fin assemblies may be reflective or contain lighting means. The entire motor, shaft, and fin assembly is encased in a translucent sphere which may also rotate and include light reflective means.
The patent to Goettsche, U.S. Pat. No. 4,394,656, issued on Jul. 19, 1983, for Sound Display Apparatus Having Separation Control, discloses the use of multiple band pass filters to divide the audio frequency spectrum. A reference signal is derived from each of the band pass filters and subsequent envelope detectors which represents the average value of the multiple frequency limited signals. Each of the frequency limited signals is compared to the reference signal and lamp selection occurs for each frequency limited signal that exceeds the reference signal. Means are also provided for supplying a varying signal to the reference signal to cause the reference signal to cyclically vary about the average value. As sound level varies, the cyclic reference signal variation alters lamp illumination time to cause lamp brightness to change in accordance with sound level.
The patent to Haddad, U.S. Pat. No. 4,376,404, issued on Mar. 15, 1983, for Apparatus For Translating Sound into a Visual Display, dicloses the use of filters to separate electrical audio signals into a plurality of discrete tones within the audio range. A logic circuit is used to select the highest frequency tone to illuminate one of a plurality of colored lamps. The intensity of the selected lamp is regulated by a voltage representing the amplitude envelope of the audio signal as modified by an automatic level control circuit. An automatic level control circuit is also used to modify the audio electrical signal from which the above mentioned tones are derived by means of tone detectors. Similarly, a low band pass filter and automatic level control circuit are used to derive a beat signal pulse to fluid valves for pulsating liquid discharge representing the rhythm of the sound source.
The prior art relies on electrical filtering techniques to divide the audio frequency spectrum into components for display, various logical criteria to determine color selection, electromechanical devices to portray a sense of movement, and direct lamp illumination, reflective media, or diffusing media to display lighting effects. The purpose of such apparatus is to enhance the enjoyment of music listening by the addition of a visual impression of the music. In view of the subtlety of great classical music, or of popular music, refinement of visual interpretation is of utmost significance. Yet, electrical filtering techniques are incapable of precisely uniform frequency representation across the spectrum segment of interest. Also, mechanical contrivances for producing a sense of motion tend to produce and element of artificiality rather than an aesthetically pleasing portrayal of music. The prior art is therefore, at best, crude in its visual interpretation of music and there is much opportunity for refinement.
Accordingly, it is a principal object of the present invention to achieve precise frequency division without unwanted band edge effects and to produce an interesting visual display sensitive to small variations in loudness, frequency content, and time related effects in music. It is another principal object of the present invention to be capable of sufficiently inexpensive implementaton for home use by individuals, as well as to be practical for public display purposes.